<em>import React from 'react'</em>

<em>export default ( <q>props</q> ) =></em> {
	<q>props.history</q>.<b>listen</b>( (<s>location</s>,<s>action</s>) => {
		<em>const</em> { 
			<i>pathname</i>, 	<em>// </em> <u>/home</u>
			<i>search</i>, 		<em>// </em> <u>?id=10&&code=20</u>
			<i>hash</i>, 		<em>// </em> <u>#10</u> 	<em>#/home#10</em>
			<i>state</i>		<em>// </em> <u>{ }</u> 
		} = <s>location</s>
		
		<em>const actions</em> = <s>action</s> 		<em>// 首次进入、前进、后退		=== </em> <b>POP</b>
								<em>// props.history.push( ) 		=== </em> <b>PUSH</b>
								<em>// props.history.replace( ) 	=== </em> <b>REPLACE</b>
	})
	<em>return null</em>
}
